Shocklets, SLAMS, and field-aligned ion beams in the terrestrial foreshock

We present Wind spacecraft observations of ion distributions showing field-aligned beams (FABs) and large-amplitude magnetic fluctuations composed of a series of shocklets and short large-amplitude magnetic structures (SLAMS). We show that the SLAMS are acting like a local quasi-perpendicular shock reflecting ions to produce the FABs. Previous FAB observations reported the source as the quasi-perpendicular bow shock. The SLAMS exhibit a foot-like magnetic enhancement with a leading magnetosonic whistler train, consistent with previous observations. The FABs are found to have T_b ~ 80-850 eV, V_b/V_sw ~ 1-2, T_{b,perp}/T{b,para} ~ 1-10, and n_b/n_i ~ 0.2-14%. Strong ion and electron heating are observed within the series of shocklets and SLAMS increasing by factors \geq 5 and \geq 3, respectively. Both the core and halo electron components show strong perpendicular heating inside the feature.Comment: 11 pages, 3 EPS figures, submitted to Geophysical Research Letter

Hemicellulose hydrolysis catalysed by solid acids

Depolymerising hemicellulose into platform sugar molecules is a key step in developing the concept of an integrated biorefinery. This reaction is traditionally catalysed by either enzymes or homogeneous mineral acids. We compared various solid catalysts for hemicellulose hydrolysis, running reactions in water, under neutral pH and relatively mild temperature and pressure (120 °C and 10 bar) conditions. Sulphonated resins are highly active, but they leach out sulphonic groups. Sulphonated silicas are less active, but more stable. They have weakly and strongly bound sites and the strongly bound ones do not leach. Zeolites are moderately active and stable. Among them, H-ferrierite especially, despite its small pores, exhibited high activity as well as good recyclability

Electronic correlations in organometallic complexes

We investigate an effective model for organometallic complexes (with potential uses in optoelectronic devices) via both exact diagonalisation and the configuration interaction singles (CIS) approximation. This model captures a number of important features of organometallic complexes, notably the sensitivity of the radiative decay rate to small chemical changes. We find that for large parameter ranges the CIS approximation accurately reproduces the low energy excitations and hence the photophysical properties of the exact solution. This suggests that electronic correlations do \emph{not} play an important role in these complexes. This explains why time-dependent density functional theory works surprisingly well in these complexes.Comment: 11 pages, 6 figure

Defects as a reason of continuity of normal-incommensurate phase transitions

Almost all normal-incommensurate phase transitions observed experimentally are continuous. We show that there is not any theoretical reason for this general behaviour in perfect crystals. A normal-incommensurate phase transition that is not too far from the mean-field tricritical point should be discontinuous and it is highly improbable that so far reported normal-incommensurate phase transitions lie very far from this point. To understand this behaviour we study influence of defects on a hypothetical first-order normal-incommensurate phase transition in a pure material. We have found that this influence is strikingly different from that on other kinds of first-order phase transitions. The change of the discontinuity of the order parameter at the transition is negative and formally diverges within our approximate theory. At the same time the diminishing of the phase transition temperature remains finite. We interpret these results as an indication that at least some of the observed seemingly second-order normal-incommensurate transitions would be first-order transitions in defectless crystals.Comment: 17 pages, 1 figur

A questão ambiental na origem do problema agrário brasileiro e o caso da região Sul.

A especificidade do processo de apropriação privada de terras públicas no Brasil, após 1850, é o ponto de origem dos problemas ambientais atuais no espaço rural, isso porque foi desse período em diante que a ausência de limites ambientais se tornou a regra principal da aliança entre a concentração fundiária e o progresso técnico aplicado à agricultura, comprometendo dramaticamente outras formas de acesso, bem como o uso produtivo ou não produtivo das terras e seus recursos naturais. O estudo de caso realizado na região sudoeste do Paraná, no Sul do Brasil, no entanto, demonstra que, apesar de uma estrutura agrária mais democrática, a regra de ausência de limites ambientais também é reiterada. Naquela região, o impulso básico à degradação ambiental deve-se ao fato de as estratégias de reprodução da agricultura familiar estarem estreitamente associadas aos imperativos do mercado exportador de grãos

Partner behavioral responses to pain mediate the relationship between partner pain cognitions and pain outcomes in women with provoked vestibulodynia

Partner behavioral responses to pain can have a significant impact on patient pain and depression, but little is known about why partners respond in specific ways. Using a cognitive-behavioral model, the present study examined whether partner cognitions were associated with partner behavioral responses, which prior work has found to predict patient pain and depressive symptoms. Participants were 354 women with provoked vestibulodynia and their partners. Partner pain-related cognitions were assessed using the partner versions of the Pain Catastrophizing Scale and Extended Attributional Style Questionnaire, whereas their behavioral responses to pain were assessed with the Multidimensional Pain Inventory. Patient pain was measured using a numeric rating scale, and depressive symptoms were assessed using the Beck Depression Inventory–II. Path analysis was used to examine the proposed model. Partner catastrophizing and negative attributions were associated with negative partner responses, which were associated with higher patient pain. It was also found that partner pain catastrophizing was associated with solicitous partner responses, which in turn were associated with higher patient pain and depressive symptoms. The effect of partner cognitions on patient outcomes was partially mediated by partner behavioral responses. Findings highlight the importance of assessing partner cognitions, both in research and as a target for intervention. Perspective The present study presents a cognitive-behavioral model to partially explain how significant others' thoughts about pain have an effect on patient pain and depressive symptoms. Findings may inform cognitive-behavioral therapy for couples coping with PVD

Evidence of strong quasar feedback in the early Universe

Most theoretical models invoke quasar driven outflows to quench star formation in massive galaxies, this feedback mechanism is required to account for the population of old and passive galaxies observed in the local universe. The discovery of massive, old and passive galaxies at z=2, implies that such quasar feedback onto the host galaxy must have been at work very early on, close to the reionization epoch. We have observed the [CII]158um transition in SDSSJ114816.64+525150.3 that, at z=6.4189, is one of the most distant quasars known. We detect broad wings of the line tracing a quasar-driven massive outflow. This is the most distant massive outflow ever detected and is likely tracing the long sought quasar feedback, already at work in the early Universe. The outflow is marginally resolved on scales of about 16 kpc, implying that the outflow can really affect the whole galaxy, as required by quasar feedback models. The inferred outflow rate, dM/dt > 3500 Msun/yr, is the highest ever found. At this rate the outflow can clean the gas in the host galaxy, and therefore quench star formation, in a few million years.Comment: 5 pages, 3 figures, accepted for publication in MNRAS Letter

LUCIFER@LBT view of star-forming galaxies in the cluster 7C 1756+6520 at z~1.4

Galaxy clusters are key places to study the contribution of {\it nature} (i.e. mass, morphology) and {\it nurture} (i.e.environment) in the formation and evolution of galaxies. Recently, a number of clusters at z$>$1, i.e. corresponding to the first epochs of the cluster formation, has been discovered and confirmed spectroscopically. We present new observations obtained with the {\sc LUCIFER} spectrograph at Large Binocular Telescope (LBT) of a sample of star-forming galaxies associated with a large scale structure around the radio galaxy 7C1756+6520 at z=1.42. Combining our spectroscopic data and the literature photometric data, we derived some of the properties of these galaxies: star formation rate, metallicity and stellar mass. With the aim of analyzing the effect of the cluster environment on galaxy evolution, we have located the galaxies in the plane of the so-called Fundamental Metallically Relation (FMR), which is known not to evolve with redshift up to z$=2.5$ for field galaxies, but it is still unexplored in rich environments at low and high redshift. We found that the properties of the galaxies in the cluster 7C 1756+6520 are compatible with the FMR which suggests that the effect of the environment on galaxy metallicity at this early epoch of cluster formation is marginal. As a side study, we also report the spectroscopic analysis of a bright AGN, belonging to the cluster, which shows a significant outflow of gas.Comment: Accepted for publication by MNRAS, 10 pages, 6 figures, 3 table

Experimental Bounds on Masses and Fluxes of Nontopological Solitons

We have re-analyzed the results of various experiments which were not originally interested as searches for the Q-ball or the Fermi-ball. Based on these analyses, in addition to the available data on Q-balls, we obtained rather stringent bounds on flux, mass and typical energy scale of Q-balls as well as Fermi-balls. In case these nontopological solitons are the main component of the dark matter of the Galaxy, we found that only such solitons with very large quantum numbers are allowed. We also estimate how sensitive future experiments will be in the search for Q-balls and Fermi-balls.Comment: 19 pages, 7 eps figures, RevTeX, psfig.st

Models of organometallic complexes for optoelectronic applications

Organometallic complexes have potential applications as the optically active components of organic light emitting diodes (OLEDs) and organic photovoltaics (OPV). Development of more effective complexes may be aided by understanding their excited state properties. Here we discuss two key theoretical approaches to investigate these complexes: first principles atomistic models and effective Hamiltonian models. We review applications of these methods, such as, determining the nature of the emitting state, predicting the fraction of injected charges that form triplet excitations, and explaining the sensitivity of device performance to small changes in the molecular structure of the organometallic complexes.Comment: To appear in themed issue of J. Mat. Chem. on the modelling of material